4 Qualification by Similarity (Qualification Family)

A new device can be qualified either by performing full-scale quality and reliability test on the actual device or using previously qualified devices through qualification by similarity (QBS) rules. By establishing similarity between the new device and those qualified previously, repetitive tests are eliminated, allowing for timely production release. When adopting the QBS methodology, the emphasis is on qualifying the differences between a previously qualified product and the new product under consideration. The QBS rules for a technology, product, test parameter, or package shall define which attributes are required to remain fixed in order for the QBS rules to apply. The attributes that are expected and allowed to vary are reviewed and a QBS plan shall be developed, based on the reliability impact assessment above, specifying what subset of the full complement of environmental stresses is required to evaluate the reliability impact of those variations. Each new device shall be reviewed for the conformance to the QBS rule sets applicable to the device. See JEDEC JESD47 for more information.